Pluto Might Actually Just Be a Big Comet

In 2006, we learned that Pluto had been lying to us for more than seventy years—it wasn’t a planet after all, but a dwarf planet. We’ve spent the intervening decade learning to cope; My Very Educated Mother Just Served Us Nine Pies and its variants became My Very Educated Mother Just Served Us Nachos. We healed, and moved on.

But scientists have decided to re-open that old wound, and throw Pluto’s identity into debate once more. A new study claims that The Little Heavenly Body That Could isn’t a planet or a dwarf planet, but just a big old clump of comets.Popular Mechanicsreports that data from spacecraft visiting Pluto and a comet named 67P turned up some similarities:

Both Pluto and Comet 67P were made of the same stuff, which suggests that Pluto came from some comets a long time ago. Specifically, the researchers examined the heart-shaped glacier on Pluto’s surface, named Sputnik Planum, and compared the nitrogen levels inside the ice to the nitrogen levels inside 67P.

“We found an intriguing consistency between the estimated amount of nitrogen inside the glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P,” says study author Christopher Glein in a press release.